Modular recipe controlled calibration (MRCC) apparatus used to balance plasma in multiple station system

ABSTRACT

A circuit tuning radio frequency (RF) power. The circuit includes a low to mid frequency (LF/HF) tuning circuit including a variable LF/MF capacitor coupled in series with an LF/MF inductor. The LF/MF tuning circuit is coupled between ground and a common node configured to receive an RF input. The circuit includes a high frequency (HF) tuning circuit coupled in parallel to the LF/MF tuning circuit between ground and the common node. The HF tuning circuit includes a variable HF capacitor coupled in series with an HF inductor. Cross parallel isolation occurs between the LF/MF inductor of the LF/MF tuning circuit and the HF inductor of the HF tuning circuit when adjusting the variable LF/MF capacitor or variable HF capacitor.

TECHNICAL FIELD

The present embodiments relate to semiconductor substrate processingequipment tools, and more particularly, a modular recipe controlledcalibration (MRCC) apparatus used to balance plasma throughout multiplestations in a semiconductor processing system.

BACKGROUND OF THE DISCLOSURE

In multi-station semiconductor processing systems including thoseperforming deposition, input RF power is split and distributed to themultiple stations. In particular, the input RF power is split using onemodule or box for all the stations. That is, after splitting the RFpower, no feasible tuning is available on a station-by-station basis.With the use of a single control box, it is infeasible to control the RFpower delivered to each station to achieve any desired powerdistribution (balanced or unbalanced).

In addition, the real estate inside the module used for splitting the RFpower may be limited, wherein the module splits and distributes theinput RF power to multiple stations. This may be problematic asclearance and creepage limits increasingly become harder to meet,thereby introducing a risk of arcing within the internal circuity.

Further, current technology uses series elements to adjust tune theoutput RF power, as supplied through a low to mid frequency RF powerand/or a high frequency RF power. However, because of the nature of thetopology, when tuning the output RF power there is no isolation betweenthe circuit elements used for tuning. That is, tuning the low to midfrequency RF power will have an effect on the high frequency RF power,and vice versa tuning the high frequency RF power will have an effect onthe low to mid frequency RF power. To accommodate for the lack ofisolation may require additional circuit elements. However, this wouldrequire an increase in the volume of the module used for splitting theRF power, which is not always possible. Also, the additional circuit maycreate a risk of very high voltages, because of the series resonance.

In addition, current technology implements the manual tuning ofcapacitive elements within the module used for splitting the RF power,wherein the module splits and distributes the input RF power to multiplestations. However, once the capacitive element is set, the capacitorposition (and value) is not further monitored. That is, there is noactive tuning of the RF power once the capacitive element is set.Further, when communication is cut from the system or power cycle, thelast capacitor position is not known.

The background description provided herein is for the purposes ofgenerally presenting the context of the disclosure. Work of thepresently named inventors, to the extent it is described in thisbackground section, as well as aspects of the description that may nototherwise qualify as prior art at the time of filing, are neitherexpressly nor impliedly admitted as prior art against the presentdisclosure

It is in this context that embodiments of the disclosure arise.

SUMMARY

The present embodiments relate to solving one or more problems found inthe related art, and specifically to provide recipe-controlled radiofrequency (RF) power adjustment to each station of a processing chamberin a modular manner Several inventive embodiments of the presentdisclosure are described below.

Embodiments of the present disclosure include a circuit tuning RF power.The circuit includes a low frequency (LF) to mid-frequency (MF) tuningcircuit including a variable LF/MF capacitor coupled in series with anLF/MF inductor. The LF/MF tuning circuit is configured to operatebetween approximately 5 kHz (kilohertz) to 400 kHz over a low frequencyrange, and between 300 kHz to over 3 MHz (megahertz) over amid-frequency range. The LF/MF tuning circuit is coupled between groundand a common node configured to receive an RF input. The circuitincludes a high frequency (HF) tuning circuit coupled in parallel to theLF/MF tuning circuit between ground and the common node. The HF tuningcircuit including a variable HF capacitor coupled in series with an HFinductor. The HF tuning circuit is isolated from the LF/MF tuningcircuit when adjusting the variable LF/MF capacitor. In addition, theLF/MF tuning circuit is isolated from the HF tuning circuit whenadjusting the variable HF capacitor. That is, cross parallel isolationoccurs between the LF/MF inductor of the LF/MF tuning circuit and the HFinductor of the HF tuning circuit when adjusting the variable LF/MFcapacitor or variable HF capacitor.

Other embodiments of the present disclosure include an apparatus fortuning RF power. The apparatus includes an RF dual source powergenerator including an LF/MF power generator providing LF/MF power at alow to mid frequency, and an HF power generator providing HF power at ahigh frequency. For example, the LF/MF power generator is configured tooperate between approximately 5 kHz (kilohertz) to 400 kHz over a lowfrequency range, and/or between 300 kHz to over 3 MHz (megahertz) over amid-frequency range depending on its configuration. The apparatusincludes a split input RF (SIRF) distribution box configured forreceiving the LF/MF power and for receiving the HF power. The SIRFdistribution box is further configured for combining and distributing atleast one of the LF/MF power and the HF power as one or more split RFinputs. The apparatus includes one or more modular remote controlledcalibration (MRCC) circuits for one or more processing stations. EachMRCC circuit includes an LF/MF tuning circuit coupled in parallel to anHF tuning circuit between ground and a corresponding common nodeconfigured to receive a corresponding split RF input. The LF/MF tuningcircuit includes a variable LF/MF capacitor coupled in series with anLF/MF inductor, wherein the LF/MF tuning circuit is coupled betweenground and the corresponding common node. The HF tuning circuit includesa variable HF capacitor coupled in series with an HF inductor, whereinthe HF tuning circuit is coupled between ground and the correspondingcommon node. The corresponding common node is configured to provide acorresponding RF output to a corresponding station after tuning. Crossparallel isolation occurs between the LF/MF inductor of the LF/MF tuningcircuit and the HF inductor of the HF tuning circuit when adjusting thevariable LF/MF capacitor or variable HF capacitor.

Another embodiment of the present disclosure includes an assembly foruse in a process chamber for depositing a film on a wafer. The assemblyincludes an RF dual source power generator including an LF/MF powergenerator providing LF/MF power at a low to mid frequency, and an HFpower generator providing HF power at a high frequency. For example, theLF/MF power generator is configured to operate between approximately 5kHz (kilohertz) to 400 kHz over a low frequency range, and/or between300 kHz to over 3 MHz (megahertz) over a mid-frequency range dependingon its configuration. The assembly includes a split input RF (SIRF)distribution box configured for receiving the LF/MF power and forreceiving the HF power. The SIRF distribution box is further configuredfor combining and distributing at least one of the LF/MF power and theHF power as a first split RF input, a second split RF input, a thirdsplit RF input, and a fourth split RF input. The assembly includes fourMRCC circuits, including a first MRCC circuit for a first processingstation, a second MRCC circuit for a second processing station, a thirdMRCC circuit for a third processing station; and a fourth MRCC circuitfor a fourth processing station. Each MRCC circuit includes an LF/MFtuning circuit coupled in parallel to an HF tuning circuit betweenground and a corresponding common node configured to receive acorresponding split RF input. The LF/MF tuning circuit includes avariable LF/MF capacitor coupled in series with an LF/MF inductor,wherein the LF/MF tuning circuit is coupled between ground and thecorresponding common node. The HF tuning circuit includes a variable HFcapacitor coupled in series with an HF inductor, wherein the HF tuningcircuit is coupled between ground and the corresponding common node. Thecorresponding common node is configured to provide a corresponding RFoutput to a corresponding station after tuning. Cross parallel isolationoccurs between the LF/MF inductor of the LF/MF tuning circuit and the HFinductor of the HF tuning circuit when adjusting the variable LF/MFcapacitor or variable HF capacitor.

These and other advantages will be appreciated by those skilled in theart upon reading the entire specification and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments may best be understood by reference to the followingdescription taken in conjunction with the accompanying drawings.

FIG. 1A illustrates a substrate processing system illustrating theapplication of RF power to a pedestal, which is used to process a wafer,e.g., to form films thereon, in accordance with one embodiment of thepresent disclosure.

FIG. 1B illustrates a substrate processing system illustrating theapplication of RF power to a showerhead, which is used to process awafer, e.g., to form films thereon, in accordance with one embodiment ofthe present disclosure.

FIG. 2 illustrates a top view of a multi-station processing tool,wherein four processing stations are provided, in accordance with oneembodiment of the present disclosure.

FIG. 3 shows a schematic view of an embodiment of a multi-stationprocessing tool with an inbound load lock and an outbound load lock, inaccordance with one embodiment of the present disclosure.

FIG. 4A illustrates an exemplary chemical vapor deposition (CVD) systemconfigured for automatic balancing of the distribution of RF power tomultiple stations, in accordance with one embodiment of the presentdisclosure.

FIG. 4B illustrates the automatic balancing of the distribution of RFpower to multiple stations using one or more modular remote controlledcalibration (MRCC) systems, in accordance with one embodiment.

FIG. 5A is an MRCC circuit diagram configured for automatic tuning of RFpower, wherein the MRCC circuit includes a low to mid frequency tuningcircuit and a high frequency tuning circuit, in accordance with oneembodiment of the present disclosure.

FIG. 5A-1 illustrates cross parallel isolation between the LF/MF tuningcircuit and the HF tuning circuit of the MRCC diagram of FIG. 5A, inaccordance with one embodiment of the present disclosure.

FIG. 5B illustrates a three-dimensional (3D) graph showing tuning of RFpower using an MRCC circuit by adjusting a capacitor of a low to midfrequency tuning circuit that is independent of the value of a capacitorof a high frequency tuning circuit of a MRCC circuit configured forautomatic balancing of the distribution of RF power to multiplestations, in accordance with one embodiment of the present disclosure.

FIG. 5C illustrates a 3D graph showing tuning of RF power using an MRCCcircuit by adjusting a capacitor of a high frequency tuning circuit thatis independent of the value of a capacitor of a low to mid frequencytuning circuit of a MRCC circuit configured for automatic balancing ofthe distribution of RF power to multiple stations, in accordance withone embodiment of the present disclosure.

FIG. 5D illustrates a recipe controlled calibration system includingseries elements for splitting the RF power delivered to multiplestations, in accordance with one embodiment of the present disclosure.

FIG. 5E illustrates a 3D graph showing tuning of RF power using therecipe controlled calibration system of FIG. 5D that shows the effect ona high frequency tuning circuit when adjusting a low to mid frequencytuning circuit, in accordance with one embodiment of the presentdisclosure.

FIG. 5F illustrates a 3D graph showing tuning of RF power using therecipe controlled calibration system of FIG. 5D that shows the effect ona low to mid frequency tuning circuit when adjusting a high frequencytuning circuit, in accordance with one embodiment of the presentdisclosure.

FIG. 6 is a perspective view of a system configured for automaticbalancing of the distribution of RF power to multiple stations using oneor more MRCC systems, in accordance with one embodiment of the presentdisclosure.

FIG. 7A is a perspective view of an MRCC system configured for tuning ofRF power to a processing station, and including a floating motor mountfor interfacing with capacitors of a low to mid frequency tuning circuitor a high frequency tuning circuit, in accordance with one embodiment ofthe present disclosure.

FIG. 7B is a perspective view of a clamshell exterior of an MRCC systemconfigured for tuning of RF power to a processing station, in accordancewith one embodiment of the present disclosure.

FIG. 7C is a perspective view of an MRCC system configured for tuning ofRF power to a processing station illustrating the clamshell exterior ofan MRCC system configured for tuning of RF power to a processingstation, and the internal components of the MRCC system being enclosedby the clamshell exterior, in accordance with one embodiment of thepresent disclosure.

FIG. 8 shows a control module for controlling the systems describedabove.

DETAILED DESCRIPTION

Although the following detailed description contains many specificdetails for the purposes of illustration, anyone of ordinary skill inthe art will appreciate that many variations and alterations to thefollowing details are within the scope of the present disclosure.Accordingly, the aspects of the present disclosure described below areset forth without any loss of generality to, and without imposinglimitations upon, the claims that follow this description.

Generally speaking, the various embodiments of the present disclosuredescribe systems and methods that provide for balanced distribution ofRF power to multiple stations. In particular, plasma enhanced chemicalvapor deposition (PECVD) multi-station plasma modules uses RF energy toeither deposit or etch film to the wafer (e.g., 300 mm wafer, etc.).Each station is sourced with either high frequency only or combined highfrequency and low to mid frequency energy, or a combination thereof.Because of the nature of plasma, its impedance is dynamic, hence activetuning of the RF power to a station is necessary to balance the RF powerdelivered to the plasma. That is, the impedance of the plasma (acting asa load) has an effect on the delivery of the RF power. In embodiments, amodular remote controlled calibration (MRCC) system achieves balanceddistribution of RF power to each of the stations in a multi-stationplasma system.

Advantages of the RF power delivery system of embodiments of thedisclosure include a modular approach to the delivery and adjusting ofRF power to each station of a multi-station processing system. Splittinginput RF power from an RF power source for delivery to multiple stationsdoes not provide balanced power, as the impedance of the plasma at aparticular station is continually changing. By providing RF power tuningability at each station (e.g., through an MRCC circuit/module ofembodiments), power delivery can be increased or decreased as desired.As such, individual control of power and/or voltage to each station isprovided. In addition, embodiments of the present disclosure provideisolation of the RF power adjustment when adjusting either the LF/MF orHF frequency. In particular, the MRCC module uses two parallel circuitsto change the impedance of the load (e.g., plasma)—one for low to midfrequency adjusting and one for high frequency adjusting. These parallelcircuits are designed so that when one frequency is adjusted, the otherfrequency will not be affected. Further, embodiments of the presentdisclosure use absolute encoders to track down the position of eachcapacitor. In that manner, position information for a capacitor is notlost. In addition, embodiments of the present disclosure use a clamshelldesign for the MRCC module that allows an assembler to gain access tointernal componentry on three sides of the module. This allows forshorter assembly time, and lessens the cost of construction. Further,embodiments of the present disclosure use a floating motor mount tocounter axial misalignment between the capacitor and the actuatorturning the capacitor. This prevents the capacitor from seizing due tomisalignment.

With the above general understanding of the various embodiments, exampledetails of the embodiments will now be described with reference to thevarious drawings. Similarly numbered elements and/or components in oneor more figures are intended to generally have the same configurationand/or functionality. Further, figures may not be drawn to scale but areintended to illustrate and emphasize novel concepts. It will beapparent, that the present embodiments may be practiced without some orall of these specific details. In other instances, well-known processoperations have not been described in detail in order not tounnecessarily obscure the present embodiments.

Embodiments of the present disclosure relate to power delivery in plasmaprocess modules, such as those used in plasma enhanced chemical vapordeposition (PECVD) and atomic layer deposition (ALD) processes.Embodiments of the present disclosure may be implemented in variousprocess module configurations. Further, embodiments of the presentdisclosure are not limited to the examples provided herein, and may bepracticed in different plasma processing systems employing differentconfigurations, geometries, and plasma-generating technologies (e.g.,inductively coupled systems, capacitively coupled systems,electron-cyclotron resonance systems, microwave systems, etc.). Examplesof plasma processing systems and plasma process modules are disclosed incommonly owned U.S. Pat. Nos. 8,862,855, and 8,847,495, and 8,485,128,and U.S. patent application Ser. No. 15/369,110.

FIG. 1A illustrates a reactor system 100A, which may be used to depositfilms over substrates, such as those formed in CVD (e.g., PECVD) oratomic layer deposition (ALD) processes. Deposition of films ispreferably implemented in a PECVD system. As shown in the configurationof FIG. 1A, RF power is delivered to the pedestal 140, though in otherembodiments power may be delivered in other ways, such as through ashowerhead. These reactors may utilize two or more heaters, and thecommon terminal configurations may be used in this example reactor tocontrol the temperatures for uniformity or custom settings. Moreparticularly, FIG. 1A illustrates a substrate processing system 100A,which is used to process a wafer 101. The system includes a chamber 102having a lower chamber portion 102 b and an upper chamber portion 102 a.A center column is configured to support a pedestal 140, which in oneembodiment is a powered electrode. The pedestal 140 is electricallycoupled to RF power supply 104 via a match network 106. The power supplyis controlled by a control module 110, e.g., a controller. The controlmodule 110 is configured to operate the substrate processing system 100Aby executing process input and control 108. The process input andcontrol 108 may include process recipes, such as power levels, timingparameters, process gasses, mechanical movement of the wafer 101, etc.,such as to deposit or form films over the wafer 101.

The substrate processing system 100A may include multiple processingstations. For example, chamber 102 may include multiple processingstations, each station having a pedestal for supporting a wafer 101. TheRF power and frequency supplied by matching network 106 is split anddistributed by the distribution system 420. To adjust the amount of RFpower delivered to each station, one or more MRCC tuners 415 areprovided in a one-to-one relationship between an MRCC tuner 415 and astation. For example, the one or more MRCC tuners 415 can be configuredto provide balanced tuning between each of the stations such that eachstation receives an equal amount of RF power, in one embodiment. Inanother embodiment, the one or more MRCC tuners 415 can be configured toprovide desired RF powers to each of the stations, such that powerdelivered to each of the stations need not necessarily be equal.

One method includes calibrating a system with known good components andsystems. Using the voltage probe (e.g., VI probe 417) feedback isprovided back to the corresponding MRCC tuner (e.g., tuner 415) todetermine how to adjust the RF power delivery to a correspondingstation. For example, one VI probe 417 is used to determine current andvoltage for a corresponding station. As such, during operation, the VIprobe 107 can measure voltage variations due to the change in impedanceof the plasma, and can actively adjust the RF power to achieve thedesired delivery of RF power to a station during processing.

The center column also includes lift pins (not shown), each of which isactuated by a corresponding lift pin actuation ring 120 as controlled bylift pin control 122. The lift pins are used to raise the wafer 101 fromthe pedestal 140 to allow an end-effector to pick the wafer and to lowerthe wafer 101 after being placed by the end-effector. The substrateprocessing system 100A further includes a gas supply manifold 112 thatis connected to process gases 114, e.g., gas chemistry supplies from afacility. Depending on the processing being performed, the controlmodule 110 controls the delivery of process gases 114 via the gas supplymanifold 112. The chosen gases are then flown into the shower head 150and distributed in a space volume defined between the showerhead 150face that faces that wafer 101 and the wafer 101 resting over thepedestal 140. In ALD processes, the gases can be reactants chosen forabsorption or reaction with absorbed reactants.

Further, the gases may be premixed or not. Appropriate valving and massflow control mechanisms may be employed to ensure that the correct gasesare delivered during the deposition and plasma treatment phases of theprocess. Process gases exit chamber via an outlet. A vacuum pump (e.g.,a one or two stage mechanical dry pump and/or a turbomolecular pump)draws process gases out and maintains a suitably low pressure within thereactor by a close loop controlled flow restriction device, such as athrottle valve or a pendulum valve.

Also shown is a carrier ring 200 that encircles an outer region of thepedestal 140. The carrier ring 200 is configured to sit over a carrierring support region that is a step down from a wafer support region inthe center of the pedestal 140. The carrier ring includes an outer edgeside of its disk structure, e.g., outer radius, and a wafer edge side ofits disk structure, e.g., inner radius, that is closest to where thewafer 101 sits. The wafer edge side of the carrier ring includes aplurality of contact support structures which are configured to lift thewafer 101 when the carrier ring 200 is lifted by spider forks 180. Thecarrier ring 200 is therefore lifted along with the wafer 101 and can berotated to another station, e.g., in a multi-station system. In otherembodiments, the chamber is a single station chamber.

FIG. 1B illustrates a substrate processing system 100B illustrating theapplication of RF power to a showerhead, which is used to process awafer, e.g., to form films thereon, in accordance with one embodiment ofthe present disclosure. Reactor system 100B may be used to deposit filmsover substrates, such as those formed in CVD (e.g., PECVD) or atomiclayer deposition (ALD) processes. As shown in the configuration of FIG.1B, RF power is delivered to the showerhead 150, though in otherembodiments power may be delivered in other ways, such as through thepedestal 140 as in FIG. 1A.

Substrate processing system 100B is similar to system 100A, except forthe location of the delivery of the RF power. Like numbered elementsperform similar functions and have similar configurations. For example,system 100B includes a chamber 102 having a lower chamber portion 102 band an upper chamber portion 102 a. A center column is configured tosupport a pedestal 140, which in one embodiment is a grounded electrode.

A showerhead 150 is electrically coupled to a power supply (e.g., one ormore RF power generators 50) via an RF match network 106. The powersupply is controlled by a control module 110, e.g., a controller. Thecontrol module 110 is configured to operate the substrate processingsystem 100A by executing process input and control 108, as previouslydescribed. Depending on the processing being performed, the controlmodule 110 controls the delivery of process gasses 114 via the gassupply manifold 112. The chosen gasses are then flown into the showerhead 150 and distributed in a space volume defined between a showerheadface that faces the wafer 101 and the wafer resting over pedestal 140.

The substrate processing system 100B may include multiple processingstations. For example, chamber 102 may include multiple processingstations, each station having a pedestal for supporting a wafer 101. TheRF match network 106 may be coupled to an RF distribution system 420that supplies power to the system 100B. For example, the RF power andfrequency supplied by matching network 106 is split and distributed bythe distribution system 420 to each of the stations. Also, the RF powerbeing delivered to a station is passed through a VI probe 417 forsensing a voltage of the showerhead, during operation. In that manner,the RF power may be adjusted at each station for balanced powerdelivery, or for desired power delivery.

To adjust the amount of RF power delivered to each station, one or moreMRCC tuners 415 are provided in a one-to-one relationship between anMRCC tuner 415 and a station. For example, the one or more MRCC tuners415 can be configured to provide balanced tuning between each of thestations such that each station receives an equal amount of RF power, inone embodiment. In another embodiment, the one or more MRCC tuners 415can be configured to provide desired RF powers to each of the stations,such that power delivered to each of the stations need not necessarilybe equal.

FIG. 2 illustrates a top view of a multi-station processing tool,wherein four processing stations are provided. This top view is of thelower chamber portion 102 b (e.g., with the top chamber portion 102 aremoved for illustration), wherein four stations are accessed by spiderforks 226. Each spider fork, or fork includes a first and second arm,each of which is positioned around a portion of each side of thepedestal 140. In this view, the spider forks 226 are drawn indash-lines, to convey that they are below the carrier ring 200. Thespider forks 226, using an engagement and rotation mechanism 220 areconfigured to raise up and lift the carrier rings 200 (i.e., from alower surface of the carrier rings 200) from the stationssimultaneously, and then rotate at least one or more stations beforelowering the carrier rings 200 (where at least one of the carrier ringssupports a wafer 101) to a next location so that further plasmaprocessing, treatment and/or film deposition can take place onrespective wafers 101.

FIG. 3 shows a schematic view of an embodiment of a multi-stationprocessing tool 300 with an inbound load lock 302 and an outbound loadlock 304. A robot 306, at atmospheric pressure, is configured to movesubstrates from a cassette loaded through a pod 308 into inbound loadlock 302 via an atmospheric port 310. Inbound load lock 302 is coupledto a vacuum source (not shown) so that, when atmospheric port 310 isclosed, inbound load lock 302 may be pumped down. Inbound load lock 302also includes a chamber transport port 316 interfaced with processingchamber 102 b. Thus, when chamber transport 316 is opened, another robot(not shown) may move the substrate from inbound load lock 302 to apedestal 140 of a first process station for processing.

The depicted processing chamber 102 b comprises four process stations,numbered from 1 to 4 in the embodiment shown in FIG. 3. In someembodiments, processing chamber 102 b may be configured to maintain alow pressure environment so that substrates may be transferred using acarrier ring 200 among the process stations without experiencing avacuum break and/or air exposure. Each process station depicted in FIG.3 includes a process station substrate holder (shown at 318 for station1) and process gas delivery line inlets.

FIG. 3 also depicts spider forks 226 for transferring substrates withinprocessing chamber 102 b. The spider forks 226 rotate and enabletransfer of wafers from one station to another. The transfer occurs byenabling the spider forks 226 to lift carrier rings 200 from an outerundersurface, which lifts the wafer, and rotates the wafer and carriertogether to the next station. In one configuration, the spider forks 226are made from a ceramic material to withstand high levels of heat duringprocessing.

FIG. 4A illustrates an exemplary multi-station plasma system 400A (e.g.,chemical vapor deposition system) configured for desired distribution(e.g., automatic balancing, weighted distribution, etc.) of RF power tomultiple stations, in accordance with one embodiment of the presentdisclosure. A PECVD multi-station plasma system uses RF energy to eitherdeposit or etch film to one or more wafers.

For example, the multi-station plasma system 400A provides for activetuning of RF power for each station to balance the distribution betweenthe plasma reactors (known to be dynamic) of each station. As shown, themulti-station plasma system 400 includes an RF generator systemincluding an HF generator 401 for generating high frequency RF power andan LF/MF generator 405 for generating low to mid frequency RF power. Thehigh frequency power is operating at a high frequency (e.g.,approximately 13.56 MHz, a range between 10-20 MHz, range between 5-50MHz, range between 5-100 MHz). The low frequency power is operating alow frequency (e.g., ranging between 360 kHz to 440 kHz, ranging between200 kHz to 700 kHz, and ranging between 100 kHz to 900 kHz). Themid-frequency power is operating at a mid-frequency (e.g., rangingbetween 200 kHz to 500 kHz, ranging between 400 kHz to 800 kHz, rangingbetween 500 kHz to 1 MHz, ranging between 800 kHz to 2 MHz, and rangingbetween 1.5 MHz to 3.5 MHz). Each generator is split into multipledistribution channels, wherein each channel powers a plasma reactor(e.g., station). The power consumption at each station depends on eachreactor's condition (e.g., the plasma impedance which is dynamic). Forexample, the high frequency RF generator 401 is connected to a matchingnetwork 402. The power and frequency supplied by the matching network402 is delivered to the split input radio frequency (SIRF) distributionsystem 410. Also, the low to mid frequency RF generator 405 is connectedto a matching network 406. The power and frequency supplied by thematching network 406 is delivered to the SIRF distribution system 410.

The SIRF distribution system 410 splits and distributes each of the highfrequency RF power and the low to mid frequency RF power to the channels(e.g., 1 through N channels). Each station can be sourced with eitherhigh frequency RF power only, low to mid frequency RF power only, or acombination of high frequency and low to mid frequency RF powers. In oneembodiment, the RF power output of the SIRF distribution system 410 isequally distributed to each of the channels.

Each channel powers a capacitively coupled plasma (CCP) reactor as shownin FIG. 4A. For example, a first channel powers a reactor enclosingpedestal 425-1 of station 1, a second channel powers a reactor enclosingpedestal 425-2 of station 2, . . . and a Nth channel powers a reactorenclosing pedestal 425-N of station N. The power consumption depends onthe reactor condition of a corresponding station. Since CCP reactors areknown to be dynamic, embodiments of the present disclosure provide foractive tuning of the RF power to each station in order to balance thedistribution between the reactors, or to provide desired power levels toeach station. In particular, each channel includes an MRCC channelconfigured for tuning the RF power delivered through a correspondingchannel to a corresponding station. Further, each channel includes a VIprobe 417 for measuring voltage of the RF power being delivered to acorresponding station. That voltage may be used as feedback to determinethe proper voltage and/or power delivered to a station. That is, byconnecting an MRCC tuner to a corresponding VI probe, and withsufficient logic, multi-station RF auto-matching may be performed toactively balance station power, in one embodiment. Also, instead of abalanced distribution, a desired and/or calibrated imbalance may also beachieved. For example, in the first channel VI probe 417A is configuredto measure the RF power delivered by the MRCC tuner 415A to station 1,in the second channel VI probe 417B is configured to measure the RFpower delivered by MRCC tuner 415B to station 2, . . . and in the Nthchannel VI probe 417N is configured to measure the RF power delivered bythe MRCC tuner 415N to station N.

As shown in FIG. 4A, each station is configured with one or more filterboxes. In general, power sources that provide alternating current (AC)or direct current (DC) power to various components through a centercolumn of a pedestal (e.g., heater and controllers that receive voltagesignals from thermocouples to measure temperature of the heater, etc.)are protected from RF power also delivered through the center column byusing the filter boxes (e.g., RF filters) at points before and afterportions of the channels that combine RF power (low to mid frequencyand/or high frequency) with AC or DC power. For example, when highfrequency RF power is delivered to a station (e.g., delivered to a chuckthrough a center column of a pedestal), a high frequency filter box 430is also provided to isolate the high frequency RF power from any otherelectrical circuitry also present in the center column. For example, ACor DC path lines that also travel through the center column of thepedestal may be used to control heating elements within the chuck of thepedestal. As such, the high frequency filter box 430 isolates the ACpath lines from the high frequency RF power delivered through the centercolumn. Similarly, a low to mid frequency filter box 435 isolates the ACpath lines from a low to mid frequency RF power delivered through thecenter column More particularly, a high frequency filter box 430Aisolates high frequency RF power and low to mid frequency filter box435A isolates low to mid frequency RF power delivered to station 1; ahigh frequency filter box 430B isolates high frequency RF power and lowto mid frequency filter box 435B isolates low to mid frequency RF powerdelivered to station 2; . . . and a high frequency filter box 430Nisolates high frequency RF power and low to mid frequency filter box435N isolates low to mid frequency RF power delivered to station N.

FIG. 4B illustrates a block diagram of an RF power system 400Bconfigured for automatic balancing of the distribution of RF power, ordesired or weighted distribution of RF power, to a quad station module(QSM) plasma processing system using one or more MRCC systems, inaccordance with one embodiment. System 400B can be implemented withinthe multi-station plasma system 400A of FIG. 4A.

Multiple power generators are provided. For example, an RF dual sourcepower generator may include a low to mid frequency RF power generator405 providing LF/HF power, and a high frequency RF power generator 401providing HF power at a high frequency.

In addition, a split input RF (SIRF) distribution box 420 is configuredfor receiving the LF/MF power from the low to mid frequency RF powergenerator 405 and for receiving the HF power from the high frequency RFpower generator 401. The SIRF distribution box 420 is further configuredfor combining and distributing at least one of the LF/MF power and theHF power as one or more split RF outputs, each of which is provided to acorresponding MRCC module 415 as a corresponding split RF input. Forexample, SIRF distribution box 420 provides RF output 1 (455A) to MRCCtuner 415A providing adjusted RF power to station 1, and provides RFoutput 2 (455B) to MRCC tuner 415B providing adjusted RF power tostation 2, provides RF output 3 (455C) to MRCC tuner 415C providingadjusted RF power to station 3, and provides RF output 4 (455D) to MRCCtuner 415D providing adjusted RF power to station 4.

As such, the four MRCC tuners of the RF power system 400B provides asinternal RF inputs the RF powers (e.g., RF outputs) from the SIRFdistribution box 420, such that each MRCC tuner 415 has an RF input andan RF output. That is, each MRCC tuner has an RF input that is connectedto the SIRF RF output for a corresponding station. Also, each MRCC tunerhas one RF output that is provided to a station, either a pedestal or ashowerhead. For example, MRCC tuner 415A provides tuned RF power 1 topedestal or showerhead 420A of station 1, MRCC tuner 415B provides tunedRF power 2 to pedestal or showerhead 420B of station 2, MRCC tuner 415Cprovides tuned RF power 3 to pedestal or showerhead 420C of station 3,and MRCC tuner 415D provides tuned RF power 4 to pedestal or showerhead420D of station 4. In one embodiment, the RF power delivered to eachstation is balanced and/or approximately equal). In another embodiment,the RF power delivered to each station is imbalanced according to adesired distribution.

In addition, MRCC controller 450 controls operations of each of the MRCCtuners 415A-415D (e.g., provides setting for balanced distribution,manual distribution, described distribution, etc.). For example, MRCCcontroller 450 may provide control signals for adjusting a value of acorresponding variable capacitor, wherein by tuning the variablecapacitor, RF power output of a corresponding MRCC tuner can beadjusted.

In particular, each MRCC tuner 415 includes an RF circuit with twoparallel circuit paths, as described below in FIG. 5A. Each parallelcircuit path includes a series resonant circuit with resonance that isabove the fundamental frequency of operation, either LF/MF or HF.Further, both parallel circuits are designed to adjust the power ofeither LF/MF or HF by adjusting the value of the variable capacitorsrespectively. The power response to the adjustment is dependent on theplasma load impedance of the station.

FIG. 5A is an MRCC circuit diagram 500A configured for automatic tuningof RF power, wherein the MRCC circuit includes a low to mid frequencytuning circuit and a high frequency tuning circuit, in accordance withone embodiment of the present disclosure. MRCC circuit diagram 500A hasa wide capacitance range that provides a large tuning range with minimalhigh frequency and low to mid frequency cross-talk. As shown, the MRCCcircuit 500A includes an LF/MF tuning circuit 701 coupled in parallel toan HF tuning circuit 702 between ground and a corresponding common node510 that is configured to provide a corresponding split RF input (e.g.,receives split RF output from the SIRF distribution box 420, that isthen internally provided as an RF input). The parallel circuits whentuned change the impedance of the load. In particular, inserting theMRCC circuit diagram 500A into the RF path impedes the load byincreasing or decreasing the energy and/or power going to acorresponding station. Further, the LF/MF tuning circuit 701 and the HFtuning circuit 702 are designed such that when one is adjusted, theother circuit is not affected.

The LF/MF tuning circuit 701 includes a variable LF/MF capacitor 530that is coupled in series with an LF/MF inductor 520. The LF/MF tuningcircuit is coupled between ground and the corresponding common node 510.In one embodiment, the resonance of the LF/MF tuning circuit 701 isabove the fundamental frequency of operation (LF/MF frequency). In oneembodiment, the variable LF/MF capacitor 530 has a value between 5-700picofarads (pf), though in other embodiments the value may exceed therange. In one embodiment, the variable LF/MF capacitor 530 has a valuebetween 15-650 picofarads (pf), though in other embodiments the valuemay exceed the range. In one embodiment, the variable LF/MF capacitor530 has a value between 100-400 picofarads (pf), though in otherembodiments the value may exceed the range. In one embodiment, thevariable LF/MF capacitor 530 has a value between 200-300 picofarads(pf), though in other embodiments the value may exceed the range. TheLF/MF tuning circuit 701 is tuned and/or adjusted by varying the valueof the LF/MF capacitor 530. As such, LF/MF power is adjusted byadjusting the value of the variable LF/MF capacitor 530. In oneembodiment, the LF/MF inductor 520 has a value found within a rangebetween 10 and 40 microhenrys (uH). In one embodiment, the LF/MFinductor 520 has a value of 24 microhenrys (uH), though in otherembodiments, the value may be different.

The HF tuning circuit 702 includes a variable HF capacitor 535 that iscoupled in series with an HF inductor 525. The HF tuning circuit 702 iscoupled between ground and the corresponding common node. In oneembodiment, the resonance of the HF tuning circuit 702 is above thefundamental frequency of operation (HF frequency). In one embodiment,the variable HF capacitor 535 has a value between 2-75 picofarads (pf),though in other embodiments the value may exceed the range. In oneembodiment, the variable HF capacitor 535 has a value between 5-50picofarads (pf), though in other embodiments the value may exceed therange. In one embodiment, the variable HF capacitor 535 has a valuebetween 10-30 picofarads (pf), though in other embodiments the value mayexceed the range. In one embodiment, the variable HF capacitor 535 has avalue between 15-25 picofarads (pf), though in other embodiments thevalue may exceed the range. The HF tuning circuit 702 is tuned and/oradjusted by varying the value of the HF capacitor 535. As such, HF poweris adjusted by adjusting the value of the variable HF capacitor 535. Inone embodiment, the HF inductor 525 has a value found within a rangebetween 3 and 30 microhenrys (uH). In one embodiment, the HF inductor525 has a value found within a range between 5 and 25 microhenrys (uH).In one embodiment, the HF inductor 525 has a value of 16 microhenrys(uH), though in other embodiments, the value may be different. In oneembodiment, the value of the HF inductor 525 is smaller than the valueof the LF/MF inductor 520.

As previously described, the LF/MF tuning circuit 701 is tuned and/oradjusted by varying the value of the LF/MF capacitor 530, and the HFtuning circuit 702 is tuned and/or adjusted by varying the value of theHF capacitor 535. The required values of the LF/MF capacitor 530 and thehigh frequency capacitor 535 are dependent on the process conditions inthe reactor. For example, tuning of the LF/MF tuning circuit 701 and/orHF tuning circuit 702 provides for tuning of the voltage presented tothe corresponding reactor and/or tuning of the power delivered to thecorresponding reactor. Specifically, the MRCC circuit diagram 500A usesmultiple parallel circuits (e.g., the LF/MF tuning circuit 701 and theHF tuning circuit 702) as a phase shifter to provide an impedance changefor a specific source frequency. As such, a change in impedance willchange the power delivered to the particular load (station). In thatmanner, as the load changes (e.g., the plasma dynamically changes itsimpedance during processing) the MRCC circuit is configured toautomatically adjust its impedance to deliver the proper power to theload (e.g., balanced power, desired power, etc.). Furthermore, inembodiments, the values of the LF/MF capacitor 530 and HF capacitor 535are synchronized with changes in process conditions either through onetuning for an entire processing sequence or through tuning at multiplecritical steps within a processing sequence.

After tuning the MRCC circuit diagram 500A, the corresponding commonnode 510 is configured to provide a corresponding RF output to acorresponding station. That is, the RF input is now adjusted andprovided as an RF output to the corresponding station.

In embodiments, the LF/MF tuning circuit 701 and the HF tuning circuit702 are designed to have isolation to avoid interference between theirrespective source frequencies. In addition, these circuits avoidresonance through its adjustment range to prevent drastic increase incurrent to one station. Below is the impedance equation of a MRCCcircuit diagram 500A.

$\begin{matrix}{{{zMRCC}(f)} = \frac{\begin{bmatrix}{\left( {\frac{1}{{\omega(f)} \times C_{LF}} + {{\omega(f)} \times L_{LF}}} \right) \times} \\\left( {\frac{1}{{\omega(f)} \times C_{H\; F}} + {{\omega(f)} \times L_{H\; F}}} \right)\end{bmatrix}}{\begin{bmatrix}{\left( {\frac{1}{{\omega(f)} \times C_{LF}} + {{\omega(f)} \times L_{LF}}} \right) +} \\\left( {\frac{1}{{\omega(f)} \times C_{H\; F}} + {{\omega(f)} \times L_{H\; F}}} \right)\end{bmatrix}}} & (1)\end{matrix}$

FIG. 5A-1 illustrates cross parallel isolation between the LF/MF tuningcircuit and the HF tuning circuit of the MRCC diagram of FIG. 5A, inaccordance with one embodiment of the present disclosure. In particular,the HF tuning circuit is isolated from the LF/MF tuning circuit whenadjusting the variable LF/MF capacitor. Also, the LF/MF tuning circuitis isolated from the HF tuning circuit when adjusting the variable HFcapacitor. Specifically, cross parallel isolation occurs between theLF/MF inductor of the LF/MF tuning circuit and the HF inductor of the HFtuning circuit when adjusting the variable LF/MF capacitor or variableHF capacitor. As shown, when the LF/MF capacitor 530 is adjusted, the HFinductor 525 in the parallel circuit for the HF tuning circuit 702operates to present a high impedance, thereby isolating the HF tuningcircuit 702 when the LF/MF tuning circuit 701 (e.g., the LF/MF capacitor530) is being adjusted. Also, when the HF capacitor 535 is adjusted, theLF/MF inductor 520 in the parallel circuit for the LF/MF tuning circuit701 operates to present a high impedance, thereby isolating the LF/MFtuning circuit 701 when the HF tuning circuit 702 (e.g., the HFcapacitor 535) is being adjusted. That is, each of the low to midfrequency and high frequency inductors provide cross parallel isolationwhen adjusting the opposing capacitor of the opposing or cross tuningcircuit.

FIGS. 5B and 5C illustrate examples of adjusting power using the MRCCcircuit diagram 500A with a 1 KW input power (e.g., internal RF input).As described, power is adjusted through varying one or more of the LF/MFcapacitor 530 and HF capacitor 535. In FIGS. 5B and 5C, the values ofthe LF/MF capacitor 530 and HF capacitor 535 are expressed as rangepercentages of total available values for capacitance. In particular,FIGS. 5B and 5C show simulation results using 13.56 MHz for the highfrequency and 400 kHz as the low to mid frequency, with a 1 kW inputpower. As shown, FIGS. 5B and 5C demonstrate the adjustability andisolation between the circuits for each frequency.

In particular, FIG. 5B illustrates a three-dimensional (3D) graph 500Bshowing tuning of RF power using an MRCC circuit by adjusting acapacitor of a low to mid frequency tuning circuit (e.g., LF/MFcapacitor 530 of LF/MF tuning circuit 701) that is independent of thevalue of a capacitor of a high frequency tuning circuit (e.g., HFcapacitor 535 of HF tuning circuit 702) of a MRCC circuit configured forautomatic balancing of the distribution of RF power to multiple stationsor a desired distribution of RF power, in accordance with one embodimentof the present disclosure. Graph 500B includes a Z-axis 541 showingpower, an X-axis 542 showing the value of the LF/MF capacitor 530, and aY-axis 542 showing the value of the HF capacitor 535. In particular,isolation between the LF/MF tuning circuit 701 and the HF tuning circuit702 is achieved when tuning the MRCC circuit diagram 500A. In oneembodiment, the HF tuning circuit 702 is isolated from the LF/MF tuningcircuit 701 when adjusting the variable LF/MF capacitor 530. Forexample, when a corresponding split RF input has a low to mid frequencycomponent (e.g., low to mid frequency of 400 kHz), the HF inductor 525presents a high impedance to the corresponding split RF inputeffectively isolating the HF tuning circuit 702 from the LF/MF tuningcircuit 701 when adjusting the variable LF/MF capacitor 530. As shown,for a particular value of the LF/MF capacitor 530, the power level isconstant no matter the value of the HF capacitor 543. That is, eventhough the HF capacitor 543 may change in value for a particular valueof the LF/MF capacitor 530, the power level is constant.

FIG. 5C illustrates a 3D graph 500C showing tuning of RF power using anMRCC circuit by adjusting a capacitor of a high frequency tuning circuitthat is independent of the value of a capacitor of a low to midfrequency tuning circuit of a MRCC circuit configured for automaticbalancing of the distribution of RF power to multiple stations, inaccordance with one embodiment of the present disclosure. Graph 500Cincludes the same axis as graph 500B of FIG. 5B, and includes a Z-axis541 showing power, an X-axis 542 showing the value of the LF/MFcapacitor 530, and a Y-axis 542 showing the value of the HF capacitor535. In particular, isolation between the LF/MF tuning circuit 701 andthe HF tuning circuit 702 is achieved when tuning the MRCC circuitdiagram 500A, for example. In one embodiment, the LF/MF tuning circuit701 is isolated from the HF tuning circuit 702 when adjusting thevariable HF capacitor 535. For example, when a corresponding split RFinput has a high frequency component (e.g., high frequency of 13.56MHz), the LF/MF inductor 520 presents a high impedance to thecorresponding split RF input effectively isolating the LF/MF tuningcircuit 701 from the HF tuning circuit 702 when adjusting the variableHF capacitor 535. As shown, for a particular value of the HF capacitor535, the power level is constant no matter the value of the LF/MFcapacitor 530. That is, even though the LF/MF capacitor 530 may changein value for a particular value of the HF capacitor 535, the power levelis constant.

FIGS. 5D-5F illustrate a recipe controlled calibration circuit 500Dconfigured for calibrating low frequency RF power and/or high frequencyRF power, and simulation results showing the power response whenadjusting capacitors in the calibration circuit 500D, in one embodiment.

In particular, FIG. 5D illustrates a recipe controlled calibrationcircuit 500D including series elements for splitting the RF powerdelivered to multiple stations, in accordance with one embodiment of thepresent disclosure. Circuit 500D includes node 1 for receiving lowfrequency RF_IN. Node 1 is coupled to LF inductor 501, which is coupledin parallel to a variable LF capacitor (LF Cap) 502, both of which iscoupled to node 2. Node 2 is coupled to low frequency capacitors 503 and504 in parallel. A parallel circuit includes a low frequency inductor505, a capacitor 506, capacitor 507, and capacitor 508, all coupled inparallel between node 1 and node 2. Capacitor 516 is coupled betweennode 1 and node 4 configured for receiving high frequency RF_IN.Variable HF capacitor (HF Cap) 515 is coupled between node 2 and ground.Inductor 517 is coupled between node 1 and node 5, which providesRF_OUT.

Also, FIGS. 5E and 5F show simulations that suggest that the recipecontrolled calibration circuit 500D is not fully isolated. Inparticular, FIG. 5E illustrates a 3D graph showing tuning of RF powerusing the recipe controlled calibration system of FIG. 5D that shows theeffect on a high frequency tuning circuit when adjusting a low frequencytuning circuit, in accordance with one embodiment of the presentdisclosure. For example, in FIG. 5E, when the low frequency component(e.g., capacitor) of circuit 500D is adjusted, at a certain value forthe low frequency capacitor the power will vary depending on the valueof the high frequency capacitor. That is, the low frequency and highfrequency components influence each other and are not isolated.Similarly, FIG. 5F illustrates a 3D graph showing tuning of RF powerusing the recipe controlled calibration system of FIG. 5D that shows theeffect on a low frequency tuning circuit when adjusting a high frequencytuning circuit, in accordance with one embodiment of the presentdisclosure. In FIG. 5F, when the high frequency component (e.g.,capacitor) of circuit 500D is adjusted, at a certain value for the highfrequency capacitor the power will vary depending on the value of thelow frequency capacitor. As such, again the low frequency and highfrequency components influence each other and are not isolated. As such,the circuit 500A of FIG. 5A provides an improvement over circuit 500D ofFIG. 5D, as the low to mid frequency and high frequency components areisolated from each other when operating at their respective frequencies.

FIG. 6 is a perspective view of a system 600 configured for automaticbalancing of the distribution of RF power to multiple stations using oneor more MRCC tuning systems, in accordance with one embodiment of thepresent disclosure. As shown, system 600 includes a quadset of MRCCtuner modules needed to supports a quad station module tool. That is,the quadset includes four individual MRCC tuners, including MRCC tuners415A-415D, wherein each MRCC tuner is configured to control powerdelivery to a corresponding station. Each MRCC tuner is similarlyconfigured, and a discussion of MRCC tuner 415A provided below isrepresentative of all the MRCC tuners. In particular, FIG. 7A provides aperspective and open view of an MRCC tuner 415 (e.g., 415A) configuredfor delivery balanced and/or desired power to a corresponding station.

In one embodiment, system 600 shows a symmetric design that is forwardcompatible with future symmetric low to mid frequency RF systems, and assuch improves inherent station balancing performance. In particular,four MRCC tuning systems 415A-415D are arranged in symmetric fashionaround a center opening 690. In one embodiment, the symmetricallyarranged MRCC tuning systems 415A-415D are configured below a quadstation processing system (e.g., system shown in FIGS. 2-3) to providepower to one or more pedestals. In another embodiment, the symmetricallyarranged MRCC tuning systems 415A-415D are configured above a quadstation processing system (e.g., system shown in FIGS. 2-3) to providepower to one or more showerheads.

Each MRCC tuner 415 includes an LF/MF tuning circuit 701 and an HFtuning circuit 702, as previously described. For example, the LF/MFtuning circuit includes an LF/MF inductor 520 and an LF/MF capacitor,wherein the LF/MF tuning circuit is tuned by adjusting a correspondingLF/MF capacitor 530. Also, the HF tuning circuit includes an HF inductor525 and an HF capacitor 535, wherein the HF tuning circuit is tuned byadjusting the HF capacitor 535.

Each of the MRCC tuners are similarly configured. For example, MRCCtuner 415A includes a fan 630 for providing cooling of components withinthe MRCC tuner. In addition, each tuning circuit in the MRCC tuners 415includes an actuator 610 configured for adjusting a correspondingvariable capacitor, and an encoder 620 for measuring the value of thevariable capacitor. The actuator is configured for changing a value of acorresponding capacitor. For example, the actuator may be a motor (e.g.,stepper, servo, etc.) controlled to change the value of a variablecapacitor. For example, LF/MF tuning circuit 701 is coupled to actuator610A and encoder 620A. Similarly, HF tuning circuit 702 is coupled toactuator 610B and encoder 620B.

Because of its similar configuration, the MRCC tuners can be employed inmodular fashion, wherein one MRCC tuner 415 is associated with onestation. Modularity is implemented by providing an MRCC tuner 415 thatcan be physically separate from but attaches to a pre-existing splitinput RF (SIRF) distribution box. In particular, each MRCC tuner 415 canbe placed close to the reactor or close to the source or anywhere on thepath of the RF for that matter. As such, by inserting the MRCC tuner 415into the RF path, the load is impeded (e.g., changed) to increase ordecrease the energy going to a particular station.

In one embodiment, the MRCC tuner 415A uses absolute encoders 620 totrack down the position of each corresponding capacitor. Positioninformation may be provided as feedback to a controller. Absoluteencoders enable more accurate positioning and positioning verificationto ensure repeatable positioning and thus repeatable station to stationpower adjustment. Previously, encoders were not used for positionverification, and as such internal verification of values and positionscould not be performed for verification purposes.

Furthermore, when using absolute encoders, position information asdetermined by a corresponding encoder is not lost. That is, the absoluteencoder allows the position to be known through a power cycle withouthaving to reset the position using a homing, limit switch or hard stopfind routine. For example, the mechanical end limits and intermediatepoints of a variable capacitor can be determined and learned by anabsolute encoder. This allows for more consistent process results thatdo not change with a power cycle. Also, the use of absolute encodersdoes not exert strain on the capacitor, because the correspondingcapacitor need only be calibrated once (e.g., to determine itsmechanical end limits). As such, the integrated absolute encoders can beconfigured to track actual position and to ensure motors know where theyare with minimal change in capacitance. This eliminates the need forperforming high stress homing.

In particular, the use of absolute encoders 620 allows for the abilityto create an accurate profile of a corresponding capacitor. The two endsof the capacitor can be found by looking at the motor's perceivedposition (based on the steps/pulses sent to the motor) and compared tothe actual position of the motor (based on the absolute encoder) anddetermining a hard stop has been found when they are more than a fullstep out of sync (1.8 degrees), in one embodiment. This determined limitallows less stress on the hard stops by stopping and not “hammering” thehard stops. For example, a stepper motor exerts a semi-sinusoidal force(e.g., back electromotive force [EMF] pulse) once it jams intosomething, causing a “hammering” motion which can cause more damage ifnot stopped quickly. Checking for a full step (or less) of misalignmentbetween the motor and encoder allows for the stepper motor to stop onlyduring the first contact with the hard stop. Subsequently, the motor maybe preventing from returning to the hard stop when adjusting thecapacitor. Repeatedly hitting a hard stop can deleteriously change thefunction of the capacitor and cause the system recipe to need to beretuned, potentially after every power cycle.

Specifically, finding one hard stop will allow for a coordinate systemto be established. The capacitor health can also be checked by findingthe other hard stop (e.g., the other end) to ensure full range of tuningfor a given capacitor. The perceived number of turns as determined byfinding both hard stops can be compared to the expected number of turnsas provided by the manufacturer. If the perceived number of turns doesnot match the expected, it could point to issues with slipping of thecapacitor and motor, broken capacitor, incorrect capacitor, etc., inembodiments. Detecting these issues prior to calibration andperiodically throughout the life of an MRCC tuner provides preventivemaintenance.

FIG. 7B is a perspective view of a clamshell exterior 750 of an MRCCtuner 415 configured for tuning of RF power to a processing station, inaccordance with one embodiment of the present disclosure. The clamshellenclosure design allows an assembler to gain access through three sidesthus reducing assembly time and cost, and making assembly time for thecomponents shorter, thus reducing labor cost. For example, referring toboth FIGS. 7A and 7B, the clamshell enclosure 750 is attached to achassis 730 configured for holding at least the LF/MF tuning circuit 701and the HF tuning circuit 702. The clamshell enclosure 750 is alsoattached to a face 735 that acts as an interface between the tuningcircuits (e.g., LF/MF tuning circuit 701 and the HF tuning circuit 702)on one side and the motor 610 and encoder 620 on the other side.

More specifically, an enclosure 780 includes the chassis or base 730, afront face 735, and the clamshell exterior 750. The enclosure 780 isconfigured for enclosing the LF/MF tuning circuit 701 and the HF tuningcircuit 702. The clamshell exterior 750 includes a top 751 and aplurality of sidewalls. For example, clamshell exterior 750 includessidewalls 752A and 752B that are adjacent to the front face 735, and asidewall 752C that is opposed to the front face 735 when attached. Inaddition, a bracket 781 is attached or coupled to the front face 735.

As shown in FIG. 7A, the MRCC tuner 415 of FIG. 7A includes one or morefloating motor mounts 710 (e.g., mounts 710A and 710B) attached to theface 735 for interfacing with capacitors of the low to mid frequencytuning circuit 701 or the high frequency tuning circuit 702, inaccordance with one embodiment of the present disclosure. For example,floating motor mount 710A provides a floating interface between theLF/MF actuator 610A and the LF/MF capacitor 530, and floating motormount 710B provides a floating interface between HF actuator 610B and HFcapacitor 535.

As an illustration, the top of the floating motor mount 710, asrepresented by floating motor mount 710B, is attached to an extension736B through screws 740A and 740B. Extension 736B is attached to bracket781 which is attached to front face 735. As shown in the blow up, thebottom of the floating motor mount 710 (as represented by mount 710B) isloosely aligned with the chassis 730 by inserting tabs 720A and 720B ofmount 710 through slots (not shown) in the chassis 730. The floatingmotor mount 710B is configured to counter axial misalignment between theactuator/motor 610B and a corresponding capacitor (HF capacitor 535).Proper alignment prevents the capacitor from seizing due to axialpressure on the bearings of the capacitor or of a coupler (not shown)joining the capacitor and the motor. In addition, the floating motormount 710 can replace a machined and solid aluminum block used as amotor mount for aligning the motor and the capacitor, thereby reducingcosts and increasing the ease of installation.

The floating motor mount 710A is similarly configured as mount 710B. Inparticular, floating motor mount 710A is attached to extension 736Athrough screws. Extension 736A is attached to bracket 781 which isattached to front face 735. The bottom of floating motor mount 710A isloosely aligned with the chassis 730 by inserting tabs through slots inchassis 730. The floating motor mount 710A is configured to counteraxial misalignment between the actuator/motor 610A and a correspondingcapacitor (LF/MF capacitor 530). Proper alignment prevents the capacitor530 from seizing due to axial pressure on the bearings of the capacitoror of a coupler (not shown) joining the capacitor and the motor.

FIG. 7C is a perspective view of an MRCC tuner system configured fortuning of RF power to a processing station, in accordance with oneembodiment of the present disclosure. The MRCC tuner system includes anLF/MF tuning circuit 701 and an HF tuning circuit 702 mounted to achassis 730. The clamshell exterior 750 of the MRCC tuner is transparentto show the LF/MF capacitor 530 and the LF/MF inductor 520 of the LF/MFtuning circuit 701, and to show the HF capacitor 535 and the HF inductor525 of the HF tuning circuit 702. The clamshell exterior 750 is attachedto chassis 730 and to the face 735, wherein a fan 630 is also attachedto the clamshell exterior 750. The face 735 separates and acts as aninterface between the motor 610/encoder 620 and the corresponding tuningcircuit, as previously described. The encoders 620 provide positioninformation back to a controller that controls the motor 610 to adjustposition of the corresponding capacitor. Also, RF out 780 is shown todelivery RF power to a corresponding station.

FIG. 8 shows a control module 800 for controlling the systems describedabove. For instance, the control module 800 may include a processor,memory and one or more interfaces. The control module 800 may beemployed to control devices in the system based in part on sensedvalues. For example only, the control module 800 may control one or moreof valves 802, filter heaters 804, pumps 806, and other devices 808based on the sensed values and other control parameters. The controlmodule 800 receives the sensed values from, for example only, pressuremanometers 810, flow meters 812, temperature sensors 814, and/or othersensors 816. The control module 800 may also be employed to controlprocess conditions during precursor delivery and deposition of the film.The control module 800 will typically include one or more memory devicesand one or more processors.

The control module 800 may control activities of the precursor deliverysystem and deposition apparatus. The control module 800 executescomputer programs including sets of instructions for controlling processtiming, delivery system temperature, and pressure differentials acrossthe filters, valve positions, mixture of gases, chamber pressure,chamber temperature, substrate temperature, RF power levels, substratechuck or pedestal position, and other parameters of a particularprocess. The control module 800 may also monitor the pressuredifferential and automatically switch vapor precursor delivery from oneor more paths to one or more other paths. Other computer programs storedon memory devices associated with the control module 800 may be employedin some embodiments.

Typically there will be a user interface associated with the controlmodule 800. The user interface may include a display 818 (e.g., adisplay screen and/or graphical software displays of the apparatusand/or process conditions), and user input devices 820 such as pointingdevices, keyboards, touch screens, microphones, etc.

Computer programs for controlling delivery of precursor, deposition andother processes in a process sequence can be written in any conventionalcomputer readable programming language: for example, assembly language,C, C++, Pascal, Fortran or others. Compiled object code or script isexecuted by the processor to perform the tasks identified in theprogram.

The control module parameters relate to process conditions such as, forexample, filter pressure differentials, process gas composition and flowrates, temperature, pressure, plasma conditions such as RF power levelsand the low to mid frequency RF frequency, cooling gas pressure, andchamber wall temperature.

The system software may be designed or configured in many differentways. For example, various chamber component subroutines or controlobjects may be written to control operation of the chamber componentsnecessary to carry out the inventive deposition processes. Examples ofprograms or sections of programs for this purpose include substratepositioning code, process gas control code, pressure control code,heater control code, and plasma control code.

A substrate positioning program may include program code for controllingchamber components that are used to load the substrate onto a pedestalor chuck and to control the spacing between the substrate and otherparts of the chamber such as a gas inlet and/or target. A process gascontrol program may include code for controlling gas composition andflow rates and optionally for flowing gas into the chamber prior todeposition in order to stabilize the pressure in the chamber. A filtermonitoring program includes code comparing the measured differential(s)to predetermined value(s) and/or code for switching paths. A pressurecontrol program may include code for controlling the pressure in thechamber by regulating, e.g., a throttle valve in the exhaust system ofthe chamber. A heater control program may include code for controllingthe current to heating units for heating components in the precursordelivery system, the substrate and/or other portions of the system.Alternatively, the heater control program may control delivery of a heattransfer gas such as helium to the substrate chuck.

Examples of sensors that may be monitored during deposition include, butare not limited to, mass flow control modules, pressure sensors such asthe pressure manometers 810, and thermocouples located in deliverysystem, the pedestal or chuck, and state sensors 920 in FIGS. 9A-9C.Appropriately programmed feedback and control algorithms may be usedwith data from these sensors to maintain desired process conditions. Theforegoing describes implementation of embodiments of the disclosure in asingle or multi-chamber semiconductor processing tool.

In some implementations, a controller is part of a system, which may bepart of the above-described examples. Such systems can comprisesemiconductor processing equipment, including a processing tool ortools, chamber or chambers, a platform or platforms for processing,and/or specific processing components (a substrate pedestal, a gas flowsystem, etc.). These systems may be integrated with electronics forcontrolling their operation before, during, and after processing of asemiconductor wafer or substrate. The electronics may be referred to asthe “controller,” which may control various components or subparts ofthe system or systems. The controller, depending on the processingrequirements and/or the type of system, may be programmed to control anyof the processes disclosed herein, including the delivery of processinggases, temperature settings (e.g., heating and/or cooling), pressuresettings, vacuum settings, power settings, radio frequency (RF)generator settings, RF matching circuit settings, frequency settings,flow rate settings, fluid delivery settings, positional and operationsettings, substrate transfers into and out of a tool and other transfertools and/or load locks connected to or interfaced with a specificsystem.

Broadly speaking, the controller may be defined as electronics havingvarious integrated circuits, logic, memory, and/or software that receiveinstructions, issue instructions, control operation, enable cleaningoperations, enable endpoint measurements, and the like. The integratedcircuits may include chips in the form of firmware that store programinstructions, digital signal processors (DSPs), chips defined asapplication specific integrated circuits (ASICs), and/or one or moremicroprocessors, or microcontrollers that execute program instructions(e.g., software). Program instructions may be instructions communicatedto the controller in the form of various individual settings (or programfiles), defining operational parameters for carrying out a particularprocess on or for a semiconductor substrate or to a system. Theoperational parameters may, in some embodiments, be part of a recipedefined by process engineers to accomplish one or more processing stepsduring the fabrication of one or more layers, materials, metals, oxides,silicon, silicon dioxide, surfaces, circuits, and/or dies of a wafer.

The controller, in some implementations, may be a part of or coupled toa computer that is integrated with, coupled to the system, otherwisenetworked to the system, or a combination thereof. For example, thecontroller may be in the “cloud” of all or a part of a fab host computersystem, which can allow for remote access of the substrate processing.The computer may enable remote access to the system to monitor currentprogress of fabrication operations, examine a history of pastfabrication operations, examine trends or performance metrics from aplurality of fabrication operations, to change parameters of currentprocessing, to set processing steps to follow a current processing, orto start a new process. In some examples, a remote computer (e.g., aserver) can provide process recipes to a system over a network, whichmay include a local network or the Internet.

The remote computer may include a user interface that enables entry orprogramming of parameters and/or settings, which are then communicatedto the system from the remote computer. In some examples, the controllerreceives instructions in the form of data, which specify parameters foreach of the processing steps to be performed during one or moreoperations. It should be understood that the parameters may be specificto the type of process to be performed and the type of tool that thecontroller is configured to interface with or control. Thus as describedabove, the controller may be distributed, such as by comprising one ormore discrete controllers that are networked together and workingtowards a common purpose, such as the processes and controls describedherein. An example of a distributed controller for such purposes wouldbe one or more integrated circuits on a chamber in communication withone or more integrated circuits located remotely (such as at theplatform level or as part of a remote computer) that combine to controla process on the chamber.

Without limitation, example systems may include a plasma etch chamber ormodule, a deposition chamber or module, a spin-rinse chamber or module,a metal plating chamber or module, a clean chamber or module, a beveledge etch chamber or module, a physical vapor deposition (PVD) chamberor module, a chemical vapor deposition (CVD) chamber or module, anatomic layer deposition (ALD) chamber or module, an atomic layer etch(ALE) chamber or module, an ion implantation chamber or module, a trackchamber or module, and any other semiconductor processing systems thatmay be associated or used in the fabrication and/or manufacturing ofsemiconductor wafers.

As noted above, depending on the process step or steps to be performedby the tool, the controller might communicate with one or more of othertool circuits or modules, other tool components, cluster tools, othertool interfaces, adjacent tools, neighboring tools, tools locatedthroughout a factory, a main computer, another controller, or tools usedin material transport that bring containers of wafers to and from toollocations and/or load ports in a semiconductor manufacturing factory.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the disclosure. Individual elements or featuresof a particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the disclosure, and all such modificationsare intended to be included within the scope of the disclosure.

Although the foregoing embodiments have been described in some detailfor purposes of clarity of understanding, it will be apparent thatcertain changes and modifications can be practiced within the scope ofthe appended claims. Accordingly, the present embodiments are to beconsidered as illustrative and not restrictive, and the embodiments arenot to be limited to the details given herein, but may be modifiedwithin their scope and equivalents of the claims.

What is claimed is:
 1. A circuit tuning radio frequency (RF) power,comprising: a low frequency (LF) to mid frequency (MF) tuning circuitincluding a variable low frequency to mid frequency (LF/MF) capacitorcoupled in series with an LF/MF inductor, the LF/MF tuning circuitcoupled between ground and a common node configured to receive an RFinput supplying the RF power that is selectable, wherein in the LF/MFtuning circuit the LF/MF inductor is coupled to the common node and tothe variable LF/MF capacitor, wherein in the LF/MF tuning circuit thevariable LF/MF capacitor is coupled to the LF/MF inductor and to theground; and a high frequency (HF) tuning circuit coupled in parallel tothe LF/MF tuning circuit between the ground and the common node, the HFtuning circuit including a variable HF capacitor coupled in series withan HF inductor, wherein in the HF tuning circuit the HF inductor iscoupled to the common node and to the variable HF capacitor, wherein inthe HF tuning circuit the variable HF capacitor is coupled to the HFinductor and to the ground, wherein cross parallel isolation occursbetween the LF/MF inductor of the LF/MF tuning circuit and the HFinductor of the HF tuning circuit when adjusting the variable LF/MFcapacitor or the variable HF capacitor, wherein the common node iscoupled to an output node that is configured to provide an RF output. 2.The circuit of claim 1, wherein the RF power supplied at the RF input isprovided by an RF dual source power generator providing at least one ofLF/HF power at a low to mid frequency and HF power at a high frequency.3. The circuit of claim 1, wherein when the RF power supplied at the RFinput has a low to mid frequency component, the HF inductor presents ahigh impedance to the RF input effectively isolating the HF tuningcircuit from the LF/MF tuning circuit when adjusting the variable LF/MFcapacitor.
 4. The circuit of claim 1, wherein when the RF power suppliedat the RF input has a high frequency component, the LF/MF inductorpresents a high impedance to the RF input effectively isolating theLF/MF tuning circuit from the HF tuning circuit when adjusting thevariable HF capacitor.
 5. The circuit of claim 1, wherein the outputnode is configured to provide the RF output to a correspondingprocessing station after tuning.
 6. The circuit of claim 1, furthercomprising: an LF/MF actuator coupled to the variable LF/MF capacitorand configured for adjusting the variable LF/MF capacitor; an LF/MFabsolute encoder configured for determining a value of the variableLF/MF capacitor; an HF actuator coupled to the variable HF capacitor andconfigured for adjusting the variable HF capacitor; and an HF absoluteencoder configured for determining a value of the variable HF capacitor.7. The circuit of claim 1, wherein the LF/MF inductor has a higher valuethan the HF inductor to provide isolation between the LF/MF tuningcircuit and the HF tuning circuit when operating at a low to midfrequency or at a high frequency.